The present invention relates to efficient error recovery in systems and methods dealing with encoded video streams as well as to an encoder and to software to carry out such methods when executed on a processing device, this software being stored on a non-transitory signal storing medium.
Compression is a method to reduce the size of a data set, in particular video data, so that it requires less bandwidth during transfer. The compressed data stream can be reconstructed by using various types of prediction. Conventionally, the data set is divided into I- and P-frames so that the I frames contain the actual compressed data while the P frames are predicted from the I frames. This concept was initially introduced to enable reading of local digital media without having to first decode the complete data set.
Today, large amounts of data are transferred via a network over imperfect channels and there is an increasing need for error recovery from network transmission errors. Applications with high quality demands, for example surveillance of industrial processes, traffic surveillance, digital operating rooms, audio applications, data compression or any other application with high demand of the streamed data quality, often uses lossless compression. Many such applications also require a refresh from artefacts within a certain maximum time limit.
Existing video codec standards (e.g. h.264, MPEG4, MPEG2, . . . ) support lossless compression in theory but their solutions for error recovery are complex and expensive. One example of this is given in U.S. Pat. No. 7,899,119, which discloses how to divide the image into regions and classifies them so that only the regions with significant information will use the complex error correction code.